HD598 Bluetooth Adapter, Wireless 5.0 Stereo Audio Adapter Handsfree Receiver for Sennheiser HD598 HD558 HD518 HD598Cs HD599 HD569 HD579 Headphones

Considering how cheap it is, I was honestly surprised when it worked. This works with a DROP + SENNHEISER PC38X, which is great, but then it overrides it's great mic with it's own terrible mic. It's very lightweight which is nice but I would much prefer it be twice the weight if the battery lasted longer.Update: Annnd it's no longer working. It connects but there's no audio at all. I've tried disconnecting and reconnecting many times. This is garbage.

Pleased with this overall, but definitely approach it with fair expectations considering the cost.Running it with my 598SE headphones at max volume is probably about 40% of max on my headphone amp. Plenty loud for voice calls, watching videos, etc. but not going to blow out your eardrums.Audio quality is acceptable. Windows reports max is 2ch 16-bit 44.1kHz. Subjectively I feel like the sound is flat compared to a wired connection; given how small the transmitter is I doubt it puts out much power so that makes sense to me.The cord is just long enough to either clip to your shirt or loop up and attach to the headphone band with tape.If you want a way to make your nice headphones usable wirelessly for under $20, don't hesitate to pick this up. I wanted open-back wireless headphones that I could wear comfortably all day and that product just didn't exist, and this solved that issue for very little money. Just don't expect it to sound as good as your headphones can when connected wired to a higher power amp.

Cons:1. Found always turn off unexpectedly.2. Battery life is short.3. Difficult to turn on the pairing mode, so, if you have different devices to connect with it, it will difficult to switch to and from different devices.4. Output power is a bit lower.Pros: The adapter upgrade the old Sennheiser headphone to Bluetooth headphone easily.